1995 Es300 A/c Problem Confirmation

[tsquare]

I am a new member to this forum (located in northern New Jersey) and recently acquired a 1995 Lexus ES300 from my Dad. The car is in very good condition and has 105,000 miles on it. I have been experiencing intermittent A/C operation over the last several months. After observing it during this period, the A/C seems to work fine on slightly cooler days and blows extremely cold air, while it does not work at all on hotter days. Also, it appears to change states (from working to non-working condition) between ignition starts. I am seeing a solid green light on my A/C dashboard control unit at all times. Before checking the freon levels, I tried replacing the A/C compressor control relay (which did not fix my problem), since this is a very common problem with mid-90's Lexus models. Also, I ran the Lexus ECU HVAC diagnostics and received only the 00 code, which indicates normal working operation. Next, I measured the A/C system freon pressure levels and found 105 psi on the high side and zero or very little pressure on the low side. Essentially, there is little if any vacuum in my A/C system. I tried adding freon, but the car did not appear to take any more than about a half of a can (if any) freon. Also, when i turn on my A/C unit, the compressor clutch appears to be turning (engaging). After reading through these forums, it appears that my problem may be due to a bad (stuck) expansion valve (a common problem with mid-90's Lexus models), which is consistent with my pressure readings and driving observations over the last several months. However, before proceeding any further, I wanted to solicit other opinions to confirm that my expansion valve is the likely root-cause of my problem.

Here are a few questions that I have:

(1) Are there any additional tests that I can perform to further isolate my problem and confirm a defective expansion valve?

(2) Which front dashboard items (besides the glove box compartment) need to be removed in order to replace the expansion valve? Excluding removing the freon and recharging the system, how much time is involved in actually replacing the expansion valve?

(3) Should I also replace the drier (or any other parts), since it connects directly to the expansion valve?

(4) Would you recommend genuine parts from Lexus or are 3rd-party aftermarket parts OK for this job?

Thanks in advance for your guidance! Any help on how best to change out this part would be greatly appreciated!

[branshew]

It has been many years, but I had to replace the expansion valve on my 95 ES. In addition to being intermittent, one of the symptoms that I had was "fog" coming from my A/C vents. I believe that this is a labor intensive repair. As to whether or not you should replace anything else, I would weigh the costs against how long you plan of driving the car. I am usually not opposed to replacing inexpensive parts or wear and tear parts that are hard to access when not performing another related repair (i.e water pump w/ timing belt), but I wouldn't start throwing good money into things that aren't broken when you will need it to replace other things that will break based on the age of your vehicle.

Regardless of mileage, some things will wear out based on age. The median age of a car in the US is 9.4 years. You are 60% beyond that now. Things will wear out and break so my advice is to save your money for those items. At this point in time I wouldn't replace extra parts and I would look aftermarket.

Also - get a professional diagnosis from a reputable shop.

[lexis lexus]

T square,

I'm also have the same problems now (not when you first posted). Same intermittant ac operation, no ac diagnostic codes. I think I'll try to replace the relay (easy/cheap), but am also thinking about the expansion valve.

Based on my FSM diagnostic approach, it wants me to chase down/check 1) compressor lock sensor circuit, 2) Compressor circuit, 3) Pressure switch circuit, 4) Igniter circuit, 5) Air mix servo motor circuit, 6) Air mix damper position sensor circuit, 7) room temp sensor circuit, 8) Ambient temp sensor circuit.

Aside from not knowing where half of these sensors/circuits are, I wonder why they need to be checked if I'm getting no diagnostic codes, which I presume test the same things.

Did you solve your problem? If so how?

LL

[subydude999]

T Square,

I just picked up my 95 ES300 (48,000 miles) from Toyota who wants $1135 to replace my Air conditioning Expansion valve and Receiver Dryer. As this amount represents probably half of the car's value, i paid the $189 diagnostic fee and drove home. The car's A/C blows cold initially when turned on but then becomes warm. Have you gone ahead with your repairs, if so, do you have any advice as to the difficulty of the job? Where are these parts located? Do you know the part numbers? Any advice is welcome. I hate to give up on such a nice car! Please share your experience.

[lexis lexus]

Dude,

A few days after my post at the end of July, I decided to jump in with both feet. This was after I'd been running the ac on and off most of July. I finally saw that the compressor was seizing from time to time, and this is unfortunately the end result of a malfunctioning expansion valve. The AC kept getting more and more anemic and then seemed to just quit. So I ordered parts on line from rycompressors, and spent a few days replacing compressor, expansion valve and drier.

First, you have to get the system evacuated. Going rate at chain shops is about $130, but a local independent mechanic with the right equipment may do it for $90. That fee includes first sucking up any r134 you have in the system, and then later a vacuum evacuation and recharge when your done replacing everything.

Getting to the drier is easy, it's just below the battery, but getting the expansion valve out was a few hours and then a few hours putting it back in -- all while on my knees spelunking under the passenger side dash. There's a great post back in '07 where a member gives the full details of this task. Long story short, have to remove glove box, disconnect air bag, disconnect and remove computer, disconnect just about everything else down there, remove passenger side air duct, remove blower motor and then the blower motor housing (that was the trickiest/hardest part), remove plastic evaporator cover plate, disconnect the two ac lines going into the firewall, and then easily slide out evaporator with the expansion valve attached.

Go to napa and get replacement (ac special) o rings for the evap to expansion valve connections, expansion valve to internal ac lines, internal ac lines to firewall coupling, and don't forget the o rings for the drier as well.

Before you put anything back together, you need to flush each line in the system with ac system flush (about $12 at Autozone for a quart), using an air compressor (remember your gonna save yourself about $900 and a compressor is a handy thing to have...sort of an investment.

Take it back to the mechanic and get it evac'd and recharged. Then you're good to go, and cold.

Like I said, I replaced the compressor, and that's fairly straightforward as well, fairly accessable once you take the alternator off.

If you decide to do this, post back and I'll try to cut and paste the '07 details for the expansion valve. It's not an overly difficult job for your average shade tree guy like me.

LL